An articulated ring set includes a plurality of concentric rings connected by axles having axes of rotation that are perpendicular to the axes of symmetry of the rings. The axles are angularly offset from one another such that they are non-orthogonal and non-parallel to one another. In an embodiment, some of the rings define a race and the axles coupling the rings to other rings of the pluralit of concentric rings are slidable within the race. First and second coils may be positioned within an innermost ring and coupled to a circuit that senses current in one coil and, in response, induces a current in the other coil. Magnets in one or more other rings both induce current in the coils and are accelerated by current in the coils.